JPS5883120A - Combustion controller - Google Patents

Abstract

PURPOSE:To increase voltage to be applied to a flame during ignition and to prevent an inverter from becoming hot, by making an inverter into the one applying a rectangular wave so that a secondary side output of a transformer of the inverter is not fedback to a primary side. CONSTITUTION:When a transistor 73 is started to move toward an ''ON'' side, collector potential of the transistor 73 is decreased, a base of a transistor 74 is turned to negative potential and the transistor 74 is turned off immediately. Although the transistor 73 is turned on by making a charge current of a transistor 75 caused by resistance 77 into a base current, the transistor 4 is turned on and the transistor 73 is turned off immediately when the collector potential of the transistor 73 begins to increase by decreasing the charge current. In this manner, a rectangular wave is obtained on a secondary winding. Thus, a problem, such as temperature rise of a transistor does not occur even if a power source of a control circuit 9 and a fuel valve driving circuit 10 are applied.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion control device equipped with an igniter circuit and a flame rond type flame detection circuit. In particular, those that operate using low-voltage alternating current as a power source, and those that are used in pulse generators (two types).

The low voltage AC power supply is, for example, 24V.

A pulse slow burner is a combustor that generates flame intermittently, that is, in a pulsed manner, unlike a general combustor where a combustion flame exists continuously over time.

There are various types of pulse combustors, but for example, a pulse combustor uses a valve that controls the supply of gaseous fuel and air to the combustion chamber, a smoking chamber, and a combustion chamber to generate air column vibration at a predetermined period. (= due to the provided exhaust pipe)

Generally, the combustion chamber and exhaust pipe serve as a heat exchanger, and its operation is as follows:
Burn fuel and air through valves 1. When the gas is supplied to the chamber and ignited with an igniter, it ignites and burns, and the pressure closes the valve, while the fuel is discharged through the trachea. This 11 output creates a negative pressure in the combustion chamber, the valve opens, and fuel and air are sucked in, while the combustion chamber and 1
) 1 Air column 1 movement produced by the trachea (- Therefore, the residual combustion flame in the exhaust pipe 11 - All the warm gases are burned ≦ C 2 Return, and the inhaled air using this as an ignition source becomes an explosion. +', it burns.And due to this pressure increase by 1-, -the previous wtr <
＋"(=lJi gas is discharged. This)" LJ 1-r cycle, and this cycle is continuously repeated. In other words, combustion occurs intermittently, that is, in pulses.
・The period θ of this pulse firing, which is 1), is generally 5 (lTrz~8011z -Q).

On the other hand, the flame rod type flame]; η output circuit is split into two parts so as to contact one flame -i o)', (<1 between poles)
Applying an alternating current of about 00 to 150 cm, the alternating current generated between the poles of the CC is changed due to the flame's regulating action.
As i+4T, the value of detecting the presence or absence of flame is 0).

[Me 1 - Flame detection is performed on the positive half of the L waveform [
d and ii'tc will be done.

For this reason, a flame burning at a frequency of 50 Hz to 80 Hz is exposed to the frequency of a commercial AC power source (60 Hz O'),
When applying , there is no correlation between the two, so the flame is 4+!
There may be cases where positive alternating current is applied to the 4th part, making it impossible to detect flame. Therefore, the number of cycles θ of the two applied alternating currents is increased so that the valley pulse flame (double alternating currents overlap). For example, the number of cycles θ of the applied alternating currents is increased to 800.

This type of conventional fuel control/inhibition device will be explained with reference to FIGS. 1 and 2.

Figure 1 (2, low 1 direct pressure AC'
E is converted into a direct current by the rectifier circuit 2, and then further converted into a high frequency alternating current by an inverter 3 (2 high frequency AC 1At (2) and boosted at the same time as the igniter rotation r!r).
4. Flame rod type flame detection times (11≦5C2'
) supply 1 king. The igniter pole 6 ignites the burner 7, and the flame rod 8 serves as a flame detection circuit. Control ft
The 111 circuit 9 and the fuel valve drive circuit 10 are connected from the rectifier circuit 2'
The control circuit 9 is supplied with the igniter circuit 4,
Controls the fuel valve drive circuit lO and fuel valve 11.

The details will be explained with reference to FIG. The AC power supply l has a negative value of dAm-C2, which makes it one peak → J'-MosudanotoC
2, it is thrown in. , 'fl'E current circuit 21, 1 diode 20 and capacitor 21. Correct or θ output power waveform converter 3 is! It consists of one swing vj< and 1'l゛nos 22 or 1:).

The older oscillator circuit includes a groove 1 formed from a -1 capacitor 23, a resistor 24.25, a transistor 26, and a -r capacitor 27.28. The same wave number of the output of converter 3 is 800Hz of sine waveform, output 'r:i, Il is 10(l V
-150V. Electric power 71 quintillion Chinese power enemy 1 [by °C
When a small IS current flows through the transistor 26, the transistor 20 is turned on, and the peaks of the capacitor 28 are discharged through the transformer 22, and the transistor 26-1 (JFF) is turned on. .Next, when all transistors 26 and 76 are in the ()F lower state, (resistance 2
5 and condensation - 270) Il, 'Chang i - time fN5+
2, the transistor 26 is turned on and 1191 operations are repeated.

The igniter circuit 4 includes a diode: l(1, 31, 32
It is composed of resistors 33, 34, 35, 36, a thyristor 37, a diac 3B, a capacitor 39, 40, a transistor pulse generating circuit, and a pulse transformer 42. When the igniter circuit 4 is operated, the transistor 41 is turned off. The charging/discharging capacitor 39 is charged via the diode 30. Further, the capacitor 40 is charged via the diode 34, and when this potential becomes higher than the conduction potential of the diac 38, the charge of the capacitor 40 turns the thyristor 37 ON, and the charge of the charging/discharging capacitor 39 is transferred to the thyristor 37, the pulse transformer 42, and the diode. 31 to obtain high voltage for the igniter. The resistor 33 controls the charging pressure of the charging/discharging capacitor 39 when the igniter circuit 4 is not in operation.

The flame detection circuit 5 consists of capacitors 45, 46, resistors 48 and 49, and a part of the combustion control integrated circuit 50. AC power for flame detection is applied through a capacitor 45, and DC obtained by rectifying the flame is applied to a resistor 4.
8.49, the AC component is removed by the capacitor 46 and becomes a DC voltage, which is input to the flame signal input terminal 51 of the integrated circuit 50 for combustion opening side j of the auxiliary circuit 9.

The integrated circuit 50 is, for example, HA-16605 manufactured by Hitachi, Ltd.
W, and perform the sequence ili'l 1i111.

When the integrated circuit 50 starts ignition, the output terminal 54.5
5 is set to the LO level, the electromagnetic coil 56 of the fuel valve is energized, fuel is supplied, and the igniter circuit 4 is driven. When ignited, the output terminal 55 is set to Hi level, the transistor 41 is turned on via the resistor 57, and the igniter circuit 4 is turned on.
stop the operation.

A resistor 58, a capacitor 59, and a Zener diode 60 provide power for the integrated circuit 50. 61 is a power input terminal, and 61 is a ground terminal.

In this case, since the inverter 3 returns the output of the secondary side of the transformer 220 to the primary side, the voltage and frequency on the secondary side change depending on the magnitude of the load on the secondary side.

Therefore, when the igniter circuit 4 is operating, the voltage applied to the flame rod 8 (2) becomes low, and the flame current obtained by applying alternating current to the flame decreases, making it difficult to detect the flame during ignition. ing.

In addition, the inverter 3 is connected to the base of the transistor 26 (
Since the voltage is maintained at 2 V throughout the entire operation, there is a point in time when the base current is in the active region of the transistor, and there is a problem in that the transistor 26 generates heat due to collector loss.

Furthermore, even if the inverter 3 fails, power is still supplied to the control circuit 9 and fuel valve drive circuit 10, so the secondary sequence continues and the fuel valve opens even though the ignition is disabled. Totality (There were two problems.

The first object of the present invention is to increase the voltage applied to the flame during ignition and to prevent the inverter from generating heat.The second object is to improve safety.

The present invention uses an inverter that outputs a rectangular wave, and prevents the output from the secondary side of the transformer of the inverter from returning to the primary side.

The present invention will be explained below with reference to an embodiment shown in FIGS. 3 and 4. In FIG. 3, a rectangular wave output inverter is provided as the inverter 70 to supply alternating current to the igniter circuit 4 and flame detection circuit 5. I try to do that.

In Fig. 4, 2, the transformer 71 of the inverter 70 is 1
It consists of a secondary winding 71a, a secondary low-voltage 1L monthly winding 71b, and a high-voltage winding 71c. A DC voltage is connected to the center tap of the primary winding 71a. The oscillation circuit consists of transistors 73, 74, capacitors 75, 76, and resistors 77, 78. Between the power supply and the base (: has no starting resistance.

When the transistor 73 starts to turn on, the collector potential of the transistor 73 falls, and the base of the transistor 74 becomes a negative potential, and the transistor 74 digits (two OF
F. The transistor 73 is turned on using the charging current of the capacitor 75 by the resistor 77 as a base current.
When the charging current decreases and the collector potential of transistor 73 begins to rise, transistor 4 turns ON, and transistor 73 immediately turns OFF.

In this way, oscillation is maintained. Even though transistor 7
Even if both 3.74 are OFF from the beginning, they start up because there is ripple in the power supply. A square wave is obtained in the secondary winding.

According to this, transistors do not generate heat,
There is no need to use a power transistor.

The output voltage of the voltage winding 71b of the transformer 71 is 100~
It is about 150V. The low voltage winding 71c is provided with diodes 80, 81 and a capacitor 82 to serve as a DC power source.

A, B, C, D, E, F are A to F in Figure 2
Indicate each point. The other configurations are the same as before.

In this way, the inverter 700)
Since the output of the next side is not returned to the primary side, the output is less affected by changes in the magnitude of the load caused by the igniter 4. Therefore, flame detection during ignition can be performed without screening the applied voltage. Further, since the transistors 73 and 74 are quickly turned on and off, there is no heat generation. Therefore, there is no need to use a power transistor or the like.

Also, since it is an inverter with square wave output like this,
Even when power is supplied to the auxiliary circuit 9 and the fuel valve drive circuit 10, the transistors do not generate heat in the same order, and power can be supplied from the imperter 70 to the side cloth 4j circuit 9 and the twisted valve drive circuit IO. Therefore, -C safety can be improved. .

As described above, according to the present invention (2), the voltage applied to the flame during ignition is low, it becomes easy to detect swirling fires, and heat generation of the inverter can be prevented. Since the small gap in the fuel valve 1.1, 14 circuit can be supplied from the inverter, all aspects can be improved.

[Brief explanation of drawings]

Figure 1 shows the conventional combustion side 1i111 device i', I''.
Figure 2 shows a conventional combustion control tHI device, 'C?
FIG. 3 is a block diagram of an embodiment of the combustion-side device of the present invention, and No. 41 is a block diagram of an embodiment of the combustion-side device of the present invention.
FIG. 3 is a circuit diagram of the main part of the one-saw joint of the device M. 2... Rectifier circuit 3.70... Impark 4.
...Igniter circuit 5...Flame Rond type flame detection circuit 6.8...Electrode 9...lr'l 61i1 circuit lO...
Fuel valve drive circuit 42...Pulse transformer 71...Inverter transformer 71a...Primary winding 71b...Low voltage winding 71c...Sieve pressure winding 2

Claims (1)

[Claims] 1. An igniter circuit, a fuel valve drive circuit, a sequence control circuit for overturning these, and a sequence control circuit (
- Combustion control device consisting of a flame rond type flame detection circuit that outputs, a rectifier circuit that converts AC power into DC, and an inverter that inputs the output of the rectifier circuit and outputs AC to the igniter circuit and the flame rond type flame detection circuit ( 2. A combustion control device characterized in that the inverter outputs a rectangular voltage waveform. 2. Claim 1 (= In the inverter:
Connect the center tap of the primary winding to the rectifier circuit, connect the collector of the transistor to both ends of the primary winding with the center tap, and connect the collector of the transistor to the base of the other transistor via the capacitor and resistor. A combustion suppressor 11 device characterized in that the device is connected to the base and has no starting resistance between the power source and the base. 3. Claim 1 (2) A combustor device characterized in that the inverter supplies power to a fuel valve drive circuit or a sequence control 6111 circuit.